wcsnrtombs(3) — Linux manual page


WCSNRTOMBS(3)           Linux Programmer's Manual          WCSNRTOMBS(3)

NAME         top

       wcsnrtombs - convert a wide-character string to a multibyte

SYNOPSIS         top

       #include <wchar.h>

       size_t wcsnrtombs(char *restrict dest, const wchar_t **restrict src,
                         size_t nwc, size_t len, mbstate_t *restrict ps);

   Feature Test Macro Requirements for glibc (see

           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:

DESCRIPTION         top

       The wcsnrtombs() function is like the wcsrtombs(3) function,
       except that the number of wide characters to be converted,
       starting at *src, is limited to nwc.

       If dest is not NULL, the wcsnrtombs() function converts at most
       nwc wide characters from the wide-character string *src to a
       multibyte string starting at dest.  At most len bytes are written
       to dest.  The shift state *ps is updated.  The conversion is
       effectively performed by repeatedly calling wcrtomb(dest, *src,
       ps), as long as this call succeeds, and then incrementing dest by
       the number of bytes written and *src by one.  The conversion can
       stop for three reasons:

       1. A wide character has been encountered that can not be
          represented as a multibyte sequence (according to the current
          locale).  In this case, *src is left pointing to the invalid
          wide character, (size_t) -1 is returned, and errno is set to

       2. nwc wide characters have been converted without encountering a
          null wide character (L'\0'), or the length limit forces a
          stop.  In this case, *src is left pointing to the next wide
          character to be converted, and the number of bytes written to
          dest is returned.

       3. The wide-character string has been completely converted,
          including the terminating null wide character (which has the
          side effect of bringing back *ps to the initial state).  In
          this case, *src is set to NULL, and the number of bytes
          written to dest, excluding the terminating null byte ('\0'),
          is returned.

       If dest is NULL, len is ignored, and the conversion proceeds as
       above, except that the converted bytes are not written out to
       memory, and that no destination length limit exists.

       In both of the above cases, if ps is NULL, a static anonymous
       state known only to the wcsnrtombs() function is used instead.

       The programmer must ensure that there is room for at least len
       bytes at dest.

RETURN VALUE         top

       The wcsnrtombs() function returns the number of bytes that make
       up the converted part of multibyte sequence, not including the
       terminating null byte.  If a wide character was encountered which
       could not be converted, (size_t) -1 is returned, and errno set to

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface    Attribute     Value                            │
       │wcsnrtombs() │ Thread safety │ MT-Unsafe race:wcsnrtombs/!ps    │

CONFORMING TO         top


NOTES         top

       The behavior of wcsnrtombs() depends on the LC_CTYPE category of
       the current locale.

       Passing NULL as ps is not multithread safe.

SEE ALSO         top

       iconv(3), mbsinit(3), wcsrtombs(3)

COLOPHON         top

       This page is part of release 5.13 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at

GNU                            2021-03-22                  WCSNRTOMBS(3)

Pages that refer to this page: wcsrtombs(3)